Hmmmm, I wonder what twist rate a 55 gr. Berger will need?

[glenn asher]

http://www.saubier.com/forum/showthread.php?t=4848

According to this thread on another site, a 55 gr. Berger will be along sometime this year. I wonder just what twist rate this bullet will require? The thread really didn't specify whether it would be a Very Low Drag, or Length Tolerant Bullet (assuming the first, it would need a pretty fast twist).

Sometimes, I think they can go too far, but what do I know? Still, it might make a heckuva bullet for a .20 Dasher, .20 BR, or 5mmx35 SMc. It should do wonderful things at long distance, but for the thick jacket.......

Seems like good times for the .20s, though.......

[heikki02003]

I can't speak for the 55's, but the the 50 Bergers (BC=0.296) are shooting nice in a 1:9. One guy on another forum is getting the 50's to stabilize in a 1:11 in a 20BR at 3600fps, but Berger recomends a 1:9. With this info, I believe a 1:9 will be great for the 55's.
I'll give you my thoughts on the 55's. I don't think there will be a huge advantage in shooting the Berger 55 over the Sierra 39gr BlitzKings in a .204. Notice how nothing in the above post states what the BC is. For this reason I'll use the 50's for the comparison.

39gr Sierra BK (all stats at 3800fps)
BC = 0.287
Wind drift at 500 yards = 23.84"
Drop at 500 yards = -31.53"

50gr Berger LTB
BC = 0.296
Wind drift at 500 yards = 22.91"
Drop at 500 yards = -30.91"

Now I think 3800fps for a 55 is unrealistic, here's what a 50 looks like going 3700fps.
BC = 0.296
Wind drift at 500 yards = 23.74"
Drop at 500 yards = -33.12"

So, a 39gr BK at 3800fps has the advantage over a 50 Berger at 3700. Imagine the difference with a 55.

Now these are for 3800fps, which is the max velocity published by Berger for the 50's, whereas they publish a velocity of 4300fps for the 30 and 35's. Now we all know that 4300fps is not attainable (safely), but theoretically it is. What I'm getting at here is that you're going to need to run some pretty hot loads to get any kind of velocity out of a 55gr. The case capacity of a .204 case is approx. 29gr of powder, in my opinion it won't quite be enough. Those bullets will be ideal for guys shooting 20BR's or 20PPC's with greater case capacity.
Now don't get me wrong, I'm not coming down on the 55 grainer. Actualy I'm pretty happy as Glenn stated, it means bullet manufaturers are really behind the great 20 cals! And the benchresters shooting 20PPC's or 20BR's just got a great bullet to try. I'll stick to small light bullets that the .204 was designed to shoot.

[chip-don]

at 500 yrs i agree!! but beyond ?? for those of us who try to play out there this is good news

[trevort]

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